Control system for electric motors.



A. 1. HALL. CONTROL SYSTEM FOR ELECTRIC MOTORS.

APPLICATION FILED D'ECHI. i913.

UNTTED sTATEs PATENT oEEiCE.;

ARTHUR-J. HALL, OF WILKINSBURG, PENNSYLVANIA, IAS-SIGNORl TO WESTINGI'IOUSE -ELECTBIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

CoNTEoL SYSTEM ECE ELECTRIC MoTo'Es.

-To all/whom it mag/concern:

Be it'known that I, ARTHUR J. HALL, a. subject of the King of Great Britain, and a resident of lVilkinsburg, in the county of Allegheny and State of'Pennsylvania, have invented a new and useful Improvement in Control Systems for Electric Motors, ofv

which the following isa specification.

My invention relates to systems'of con.- trol or electric motors, and it has special reference to systems adaptedto control the operationot the electric motors ot' a motor car or electric locomotive operated upon'a direct current railway system.

One of theobjects of my invention Iis to providea system `of the above indicated character which shall be simple in arrange.- ment, easy to manipulate, and adapted to automatically eontrolithe operation of the driving motors.

Another obJect of my invention is to pro- 'vide a control system which 4shall have a plurality of economical running positions, and be adaptedto automatically control the accelerationofthe motors from rest to any one otV the running positions.

Another object of my invention is to provide a'series-parallel control system of the unit-switch type. which maybel adapted for multiple unit operation and Jfor automati cally governing a shunt transition in chang.- ing the motor connections from series to parallel arrangement.V

More specifically,ithe object of my invention is to provide an auxiliary relay which shall act in conjunction with the usual interlock switches of a unitvswitch series-par allel control system for the purpose `ot obtaining full automatic operation ofthe motors `while employing the well-known shunting method of transition.

Automatic operation of series-parallel control systems for electric railway motors has been common in the past. However, all such systems have'employed what is known as bridging transition between series y.and parallelmotor connections.

It is my purpose .to simplify the usual con'- nections and operation for automatic-ally controlling electric motors, and to provide means whereby the shunting method of transition may be employed in a -ztull automatic system.

In the accompanying drawing, Figure 1 is a .diagrammatic View ofthelmain motor cir- Specicaton of Letters Patent. Patentd Dec, 11, 1917, `Application filed December 4, 1913. Serial No. 804,644. Y

cuits and apparatus, the auxiliary control circuits being omitted. Fig. 2 is a diagram,- niatic view of the auxiliary control circuits and switching devices vfor governingthe operation and connections of the main motor circuits and apparatus, the interlock switches beingdistributed over Vthe diagram without reference `to the main switches with which they are associated, for the purpose of simplifying the diagram and rendering it clear and easy to understand. Fig. 3 is a chart of aV type familiar to those skilled in the art, vshowing the positions or the .several switchescorresponding to the several running positions or steps or the controller. Figs. 1 and 2 are shown in the drawing in' combination.

Irshall first describe the main Ymotor con- Y nections and the general operation, `after which the control circuits and operation will be set `forth with particularreterence to the relationship between thev operation of the auxiliary control apparatus and that of the m-ain motor switches.-

Referring to the drawing, the system shown comprises a supply circuit l0 which fis adapted to-deliver energy Ato a plurality of motorsrespectively having armatures A1 'and A2 `and field magnet windings 1*"1 and F2, a plurality .of resistance short-circuiting switches R1, R2, RRl, and RRZ, for .eliminatingl sections of plurality oi startn ing resistors, which, Jfor convenience, will be hereinafter referred to by the same reterf lence characters as indicate the corresponding switches, a field changing` switch marked Reverseri for establishing connections of -theield magnet windings vF1 and lF@ for forwardk or reverse operation,a pluralityV .of motorcircnitswitchesLS and S for use during the series connection of the motors, a plurality of motor circuit switches P and Gr which are employedduring 'the parallel motor connections, 'an electro-re sponsive switching `device marked Limit switch for automatically controlling the acceleration of the motors, and a return circuit E. Y .A

In the operation of the system, switches LS and 'Sare rst- Lclosed, thereby completing ,a .circuit Vfrom the' supply circuit or trolley l0 which includes acutout switch 11,

switch LS, resistors R1, R2, armature A1, 'conducting segment 12 of the ,freverser, field ma netwv'ind-,ino'V E? conductinoP seo'- ment 13 of the reverser, switch S, resistors BB1 and RRZ, armature A2, conducting segment 1st of the reverser, field magnet winding F2, conducting segment 15 or the reverser, and energizing coil of the limit switch to the return circuit E.

Thus, energy is supplied to the drivingY motors through all 'ot the starting resistors, and hence the motors are started into'operation at slow speed. The resistor switches R1, R2,Rlt1 and BH2 are' then closed successively and in accordance with the action of the limit switches, which is dependent upon the amount ot current traversing its energizing coil. Accordingly, the driving motors are gradually brought up to speed with all of the starting resistance eliminated and a series connection ot the motors established.

The transition from series to parallel connections is effected by temporarily shortcircuiting one of the motors in accordance with the well-known method ot shunting transition. In accomplishing this change of connections switch G is closed simultaneously with the opening of the resistor switches, and, thus, establishes a short-circuit connection around the motor A? which temporarily renders it ineffective as a driving unit.

' As soon as the G switch is closed, switch S is opened and switch P is closed. Upon closure of the switchP, parallel connections of the driving motors are established and full line voltage is applied to them and their respective starting resistors.

' The operation then continues automatically to eiiiect the progressive elimination of the starting resistors R1, R2, BB1 and R2 and to gradually bring the motors up to their full running speed.

Before describing the operation of the auxiliary control system, attention is directed to the interlock switches which, for convenience, will be referred to as having the same reference characters as are applied to the main switches with which they are associated. Although the interlock switches referred to, are illustrated as separate from their respective main motor switches, for the sake of clearness,V it should be understood that actually they are mechanically associated therewith and operate accordingly. These switchesV are adapted to occupy two positions, one in which the associated main switch is open and termed switch-outposition, and `the other in which the ymain switch is energized and closed and termed switch-in position.

Reference may nowbe had to Fig. 2' in which is shown a hand'loperated switching device marked Master controller comprising a plurality ot' groups of movable conducting segments 20, 21, 22 and 23, 24- and 25 and a cooperating setof'stationary contact terminals 1, 7 F, R, P, T, and 5 which` are adapted to engage certain of said conducting segments along the position-indicating lines a, e, j', and it for forward operation of the motors, and to engage the other conducting segments along the position-indicating lines is and Z for reverse operation.

A plurality ol coils F and R are employedfor energizing their respective cores, which are illustrated in Fig. 1 in connection with the reverser and which bear the same reference characters, for the purpose of moving the t reverser to its forward or reverse position.

In order tofstep down theline voltage for application to the energizing coils of the several motor circuit switches, an energyconsuming device marked Control resistor is employed, it being provided with a plurality of intermediate taps 6 and 7.

The automatic shunting transition, hereinhefore mentioned, is effected by means of an. auxiliary switching device marked Bridging relay .which merely constitutes an electro-magnetically operated switch for effecting a proper transi'er of circuits to give the desired operation.

Assuming the apparatus and circuit connections to beas shown, the operation of the system is, as follows:

Control switch y3() vis first closed, after which the master controller is moved to its irst position marked a in which a control circuitis established through contact terminal T, conducting segments 21 and 22, contact terminal and conductor 5, and the control resistor to the return circuit E. Energy is then delivered to Contact terminal of the master controller through tap and conductorv 7 Vof the control resistor, after which, a circuit is established which includes conducting segment 20, contact terminal and conductor F, interlock switch, reverser R-in and conductor 31, where thc circuit divides, one branch including energizing coil or switch LS to return circuit E, and the other branch including energizing coil of switch S, interlock switch AP-out, and interlock switch (-out to conductor E.

Thus, switches LS and Sv are energized and limit switch (if the motor current is not suticient to hold it in its -raised position) interlock S-in, interlock LS-in, interlock lil-out, energizing coil of switch R1, and interlock 13R-out to tap 6 of the control resistor.

Y Switch R1 is kthus closed in accordance with the action of the limit switch, and, thereafter, switches RR/l, R2 and .BH2 are progressively closed in an old and familiar manner which will not be described.

Thus, automatic acceleration ofthe motors is effected `to full speed with series lconnection of the motors.

-If now the master controller be lmoved to position acir'cuit is completed fromcon'- tact terminal 7 through'conductingsegment 20, conta-ct terminal and conductor P, interlock vBH2-in, and energizing coil 33 of the bridging relay to the return circuit conductor E..

The bridging relay ycloseits associated linterlock switch which immediately establishes a holding circuit from conductor 7 through interlock .BR-.in and thence, through coil 33, to .conductor E.

Concurrent-ly with the actuation of the bridging relay, its interlock' `Edt-out, which is included in circuit with conductor 6` of thecontrol resistor, is opened to interrupt the energizing circuit for vthe switches R1, RR1, R2, HB2. These switches, therefore, open to cut in theircorresponding resistors. At the same time that the bridging relay establishes its holding circuit, it also completes a circuit through its-interlock 13R-in, and energizing coil of switch Gr` to 'conductor E. Switch G is, therefore, closed -to short-circuit motor A2 temporarily. In

closing, interlock G-out is opened -which immediately denergizes the coil of switch S and causes said switch to open. In opening switch S, interlock S-out is closed, thereby permitting energy to be supplied to the energizingcoil of switch l?, which switch closes in turn. Thus the driving motors are placed in parallel arrangement with their respective starting resistors inl circuit there with. y

The operation from 'this point on7 is similar to that hereinbefore described, the resistor switches R1, BB1, R2 and :BH2 being closed `in succession in accordance vwith the action of the limit switch until the motors are brought up to full speed with full voltage across them.

It is evident, therefore, that automatic operation, including automatic shunting transition, may be effected inbringing the driving motors up to their highest speed, or, the automatic operation-may be arrested at either of the intermediate running positions @and f.

The function of the bridging relay 'is to transfer the control circuits during the shunting transition whereby the changeover of the motor connections from series to parallel may be effected without opening the motor circuit.

While I have shown and described my invention as embodying a specific arrangement is thus raised to y motors,

of circuits and apparatus, it is to be expectedA that the principles involved therein may be employed with other arrangements and connections. I therefore, intend to cover in the appended claims all modifications of the sys-V tem set forth which do not depart from the.y

said switches to insert said resistors in circuit with the parallel connected motors.

2. In a control system for` electric motors, the combination with a plurality of motors, motor circuit switches for effecting changes lin the -motor connections, and auxiliary control circuits for controlling said switches, of means .comprising a relay energized from said `auxiliary circuits for governing the operation of said switches to effect automatic shunt transition.

3. In a control system for electric motors, the combination with a plurality of motors, and a- `plurality of motor circuit switches for arranging the connections of said motors, vof means cooperating with said switches .for governing the operation thereof Y and .a relay associated therewith for-.autoinatically changing the connections of said motors `from series to parallell and shortcircuiting `one of the motors during transition.

4. .In a control system for electric motors, the-combination with a plurality of motors, and a plurality of motor circuit switches for arranging the connections o'f said motors, of .a plurality of interlocking switches associated with said motor circuit switches, `and an yauXiliary switch -cooperating therewith for automatically changing the motor connections .from series tofparallel ilthrough a shunting transition.

5. Ina fcontrol system for electric motors, :the Acombi-nation with a plurality of and a plurality lof motor `circuit switches for :arranging the connections v4of said motors, fof a .plurality of interlocking switches associated with said motor circuit switches, andan auxiliary relayswitch cooperating therewith for automatically short circuiting one of the motors during the transition from series to parallel connection.

6. In a series parallel control system for electric motors, a plurality of motors, a plurality of motor circuit switches, and a plurality of resistance-governing switches, of a plurality of interlocking switches associated with certain of said'resistance-governing switches and said motor circuit switches, an auxiliary relay switch dependent upon the operation of one of the aforesaid switches and cooperating therewith to elect automatic acceleration of said motors to full speed and to change said motors from series to parallel connectionstlirough a temporary short-circuit aroundy one of said motors.

7. In a control system for electric motors, the combination with a plurality of motors, resistance-governing switches, motor circuit switches Vfor effecting the motor connections during series operation, and motor circuit switches employed only during parallel operation, of means comprising an auxiliary relay for automatically changing said motor connections from series to parallel by a shunting transition and causing the operation of said parallel motor circuit switches.

r8. In a system orP control for 'electric motors, the combination with a plurality of motors, a controller, and a plurality of electrically-operated switches for arranging `the motor connections for series and-parallel operation, of automatic Aelectro-responsive means governed by one controller position for operating certain of said switches to effect a transition in motor-circuit connections from series to parallel-circuit relation and vfor maintaining the motor circuit unbroken. y 9. In a system of control for electric motors, the ycombination with a plurality of motors, a controller, a single set of resistors for effecting acceleration of the motors in series and in parallel-circuit relation, and a plurality otmotor-circuit switches for arranging the motor connections for series and parallel operation, and for short circuiting said resistors, of an electro-responsive relay governed by one controller position and cooperating with one of said motor-circuit switches for effecting an automatic transition of the motor circuits from series to parallel operation and for maintaining the motor circuit unbroken.

10. In a system of control for electric motors, the combination with aplurality of motors, and a plurality of motor-circuit switches for arranging the motor connections for series and parallel operation, of an interlocking switch associated with one of said motor-circuit switches and an auxiliary connections during series operation, .and`

motor-circuit switches employed only during parallel operation, of electro-responsive meansvcooperating with one of said resistance-governing switches, motor-circuit series switches and motorc1rcuit parallel .switches for automatically changing said motor connections from series to parallel through a shunting' transition.

l2. In a system of control, the combination with a plurality of motors, a controller, and means governed by saidv controller for Voperating the motors in series and in parallel-circuit` relation, of automatic means governed by said controller, when moved to a transition position, for effecting a shunting transition of the motors.

18. In a system of control, the combination with a plurality of motors, a controller, and means governed by the controller for operating' said motors in series and in parallel-circuit relation, of automatic electro- `responsive means governed by one con troller position for effecting a transition of the motoncircuit connections from series to parallel-circuit relation and for maintaining the motor circuit unbroken.

14. In a. system of control, the combination with a plurality of motors, a plurality of motor-circuit switches for arranging the motor connections for series and parallel operation, and a controller for governing the operation oi said motor-circuit switches, ot' automatic electro-responsive means governed by one controller position for elfecting a transition in motor-circuit connections from series to parallel-circuit relation and for maintaining the motor circuit unbroken.

In testimony whereof, I have hereunto subscribed my name vthis 28th day of Nov., 1913.

' ARTHUR J. HALL.

lWitnesses: i

PH MARDIs, B. B. HINES.

Copiesof this patent may ha obtained forV ve cents ea'chQby addressing the Commissioner of lateiitl,

' Washington, D. G. 

